1. Field of the Invention
This invention relates to an improved sleeve bolt and, more particularly, to a sleeve bolt having a cylindrical sleeve and an inner polygonal shaped slide member movable between a protruding orientation for coupling with a tool and a retractable orientation wherein its exterior surface is flush with the head of the sleeve bolt and external surface of the panel being coupled, the exposed longitudinal external surface of the inner slide member being essentially recess-free.
2. Description of the Background Art
In the aircraft field, external panels are normally joined with substructures through fasteners known as sleeve bolts. When installed, the external surface of a sleeve bolt must be as smooth, continuous and flush as possible with respect to the external surface of the panels. The external surface of a sleeve bolt must also be formed essentially recess-free for generating minimum air turbulence and resistance with respect to the aircraft utilizing such sleeve bolt. During installation and removal, the sleeve bolt must present a polygonally shaped component such as a hex shape, triangular, quadrilateral, pentagonal or octagonal for example, for positive engagement with a tool for the insertion and removal of the sleeve bolt.
Various approaches are disclosed in the prior art for the design of sleeve bolts. Such designs may take the form of one piece fasteners or multi-piece fastener assemblies. All such fasteners, however, recognize the need for providing a mechanism for coupling with a tool for insertion and removal of the fastener with respect to the panels being joined, and all such fasteners recognize the need for constructing the external surface of the fastener flush with the external surface of the panels with as smooth and continuous a surface as possible for abating wind turbulence which is otherwise normally generated during flight of the aircraft.
In addition, various approaches are disclosed in the patent literature for improving fasteners. Note, for example, Duran U.S. Pat. No. 4,822,227 which discloses a fastener with a bolt head having a hex socket with a releasable plug therein. The plunger portion is biased by a spring to keep it in a raised position. A working tool is used to press the plunger downward. DeLacy U.S. Pat. No. 3,078,574, discloses the concept of a bolt head having a recess which receives a separate drive socket insert therein. Stull, in U.S. Pat. No. 1,096,070 shows a common fastener having a protruding wrench engaging head.
As illustrated in other patents and commercial devices and techniques, efforts are continuously being made in an attempt to improve sleeve bolts for joining panels, as in aircraft. Such efforts are made to render such sleeve bolts more efficient, reliable, inexpensive and convenient to use. None of these previous efforts, however, provides the benefits attendant with the present invention. Additionally, the prior patents and commercial devices do not suggest the present inventive combination of component elements arranged and configured as disclosed and claimed herein. The present invention achieves its intended purposes, objects and advantages over the prior art through a new, useful and unobvious combination of component elements with the use of a minimum number of functioning parts, at a reasonable cost to manufacture, and by employing readily available material.
Therefore, it is an object of this invention to provide a stainless steel sleeve bolt for coupling together an apertured external panel and a substrate of an aircraft. The bolt comprises a cylindrical sleeve having a radially exterior surface of a cylindrical configuration at its axial external end and having internal threads at its axial internal end for threadingly coupling with a fixed substrate bolt. The bolt further comprises an inner polygonal shaped member which according to a preferred embodiment is illustrated as a hex shape having a hexagonal cross-sectional configuration positionable within the axially external end of the cylindrical sleeve and movable between a retracted orientation totally within the cylindrical sleeve and a protruding orientation partially within the cylindrical sleeve. The bolt comprises coupling means including a pair of grooves within the cylindrical sleeve extending longitudinally with the axis. A pair of ball detent members located within a diametrically extending hole of the inner hex slide cooperate with a coil spring urging the ball detents outwardly into the grooves. The longitudinal length of the grooves defines the limits of movement of the ball detent means and inner hex slide between its retracted and protruding orientations. The grooves include surface portions formed at obtuse angles from the axis of the sleeve bolt at opposite ends of the groove extremities. Other surface portions intersect and taper inwardly therefrom to a central point along the groove forming acute angles from the axis at the midpoint of the groove.
It is further a object of this invention to join panels, such as those relating to an aircraft, through a sleeve bolt which, when installed, presents an essentially smooth, continuous and essentially recess-free surface with the panels.
It is a further object of this invention to join a panel to a substructure with a sleeve bolt which presents an enlarged component for coupling with an insertion/removal tool for maximum surface area therebetween.
It is a further object of the present invention to slide an inner polygonal shaped member of a sleeve bolt between a protruding orientation for coupling with an insertion/removing tool and a retracted orientation wherein a smooth, continuous and essentially recess-free surface of the joined panels is presented.
Lastly, it is an object of the present invention to join panels more efficiently, reliably, conveniently and economically.
These purposes, objects and advantages should be construed as merely illustrative of some of the more prominent features and applications of the present invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or by modifying the invention within the scope of the disclosure. Accordingly, other purposes, objects and advantages as well as a full understanding of the invention may be had by referring to the summary herein mentioned and detailed description describing the preferred embodiments of the invention, in addition to the scope of the invention, as defined by the claims, taken in conjunction with the accompanying drawings.